Thorny dragon
Thorny Devil ( Moloch horridus )
The Thorny Devil ( Moloch horridus ) or Moloch is a native to Australia kind of Agamas. Although quite small, orange-red lizard is distinctive due to its completely covered by spines body.
The Thorny Devil lives in the arid regions of central and western Australia, where he was hiding as making a small building in which he spends the night, the entire dry season and the hot summer months. In spring and autumn it is morning and afternoon, active, and goes in search of food. The Thorny Devil feeds exclusively on ants ( Myrmekophagie ); this he stands next to a trail and lick the insects with his tongue on. Since there is little water in the desert, a system of microscopic grooves developed in his skin that transport by capillary water from rain and fog to his mouth.
Features
Full-grown, female Thorny Devil have a head -body length of 8-11 cm and weigh up to about 89 g, while males with a maximum of 9.6 cm and a maximum of 49 g remain significantly smaller. The species is generally built quite sturdy, and has a short tail. The most striking feature is the strong, thorn-like spines on the head, trunk, legs, and tail. On the neck there is a notable, spiny protuberances. All spines of thorn devil are made of keratin.
The animals are colored orange to yellow, and have black spots and bright longitudinal stripes on. The base color is determined by the color of the sand, individuals from areas with reddish sand are for example tend to reddish in color than other populations. In addition, the Thorny Devil has the ability to physiological color change, which manifests itself in the lighter staining of active spike devils.
The feces of devils thorn is glossy black, ovoid, relatively large and practically unique. Thorny devil lay in their action spaces often have special places on where they settle their feces regularly - these accumulations of up to about 20 droppings indicate the presence of thorn devils.
The Thorny Devil runs with jerky movements, and holds his tail curved upwards like.
Distribution and habitat
The Thorny Devil lives in particular the drylands of Central Australia in SW Queensland, South Australia, the Northern Territory and south - western Australia. Unsecured, but are possible occurrence in the Nullarbor desert as well as in northwest New South Wales. In most of its range the Thorny Devil sandy desert inhabited with spinifex vegetation, acacia ( " Mulga " ) and eucalypts, especially in southwest Western Australia also deposits in the Mallee are known. On stone floors, the species is rare.
Hiding places and activity
Thorny devil are diurnal loner. They use self-dug burrows 5-10 cm depth as a hiding place, or they hide in spinifex.
During the coldest (June, July ) and the warmest (January, February ) months Thorny Devil remain largely inactive in hiding. They are active in the fall and in particular from late winter to early summer, when mating and oviposition take place. At other times, the activity pattern is bimodal. The night they rest in their hiding place, only to bask in the morning. By late morning, they look for food, the hot lunch to spend time in their shelter, and go again in the afternoon in search of food.
In radio telemetry studies in the Great Victoria Desert male Thorny Devil laid on average 66.6 m per day back, Females, however, only 31.7 m. In one case, a male lay around 300 meters back in a day. It is not known whether Thorny devil have used a long time action space; because ants are often spatially unevenly distributed and variable, it is perhaps the Thorny Devil is a semi-nomadic.
Nutrition
The Thorny devil eats only small, black ants Iridomyrmex from the former group, which has now spread to many other genres. Usually about 750 ants are captured daily, then take 1-2 cc in the stomach. In the stomach of the mandrel up to 2500 devil ants can be found which will take about 5 cc.
To hunt for ants Thorny Devil positioned next to an ant trail; this does not need to run on the ground, Thorny Devil loot also arboreal ants. To this end, they lurk on tree trunks, sometimes in the upright position and support with the front legs from the trunk. The animals placed very close to the ant trails and catch the ants with his tongue. The Thorny Devil is the fastest known eaters among the iguana -like (1 Ameise/350 ms) which can be explained by a number of adjustments. Most lizards jump into a forward movement on their prey open their mouths and initially slower than towards the end. The Thorny Devil on the other hand does not have to rush to the ant, as he can go close to ant trails and has a relatively long neck. Instead of initially slow to open his mouth, he opens it right at maximum speed and leaves shoot out the tongue. Even the Thorny Devil takes little time to swallow. Free-living Thorny Devil consume ants at rates of up to 12 ants / min, over short periods of well 1 ant / sec.
Water Resources
The microstructure of his shed dress enables him to take up water drops from dew, fog, and the very rare rains, which are guided by the structure of its body surface to the mouth. The top keratin layer of the scales is sculpted like a honeycomb; these combs have diameters of 10-20 microns and 5 microns deep. This surface structure makes the body surface of the mandrel devil highly hydrophilic and water drops run along the skin of a thorn devil down to a thin film of water and not from animal. The water then passes into a system of microscopic grooves between the scales by capillary force to the mouth of thorn devil.
Standing water is often not available and is not drunk. The Thorny Devil metabolized daily 0.3 ml of water, which is comparatively little for a lizard of its size.
Reproduction and Development
Little is known about the reproduction of the devil thorn in nature. It is produced only one clutch per year. According to studies of ovarian follicles and testis, it seems that both pairings in autumn (May ) and in spring (August and September ) can take place. Eggs are laid only in late spring - some females store sperm from pairings from the last fall. It is not known how to find partners, there were, however, already observed by two male and two females mating retention.
In the Great Victoria Desert three females were observed laying eggs; they lay their eggs in September, October or November in self-dug nesting chambers. Cavities as nest are unusual among reptiles; most species lay their eggs in loose substrate. The nests included 6-7 eggs and made from 34.2 to 41.7 % of body weight of pregnant females from. The juveniles hatched after 124-127 days and measured on average 3.57 cm SVL. The juveniles eat after hatching the egg shells - an unusual practice for Squamata. This is probably the calcium supply. Finding the eggshell is facilitated by an air-filled Nistkammer.
Thorny devil grow up to their age of 6; Males stay smaller than females because their growth rate decreases earlier. The life expectancy is 20 years maximum.
Natural enemies and avoiding enemies
To the hunters of thorn devils include birds of prey, snakes, dingoes, foxes and lizards. When approached by a predator, Thorny Devil freeze in their current position, often with even a raised leg. Thus, they are difficult to see, especially by their spines, they are well camouflaged. However, the spikes do not hurt the stomach walls of predators.
System
The first description of thorn devil was made in 1841 by the zoologist John Edward Gray ( 1800-1875 ), who was referring to a 1840 by John Gould ( 1804-1881 ) in London issued copy. The genus name Moloch headed Gray from the Moloch cult, horridus could in Latin both for the rough, prickly body covering the thorn devil as well as "terrible" are.
From the Thorny Devil no subspecies are recognized.
Phylogeny
The phylogeny of the Australian agamid was elucidated by cladistic analyzes of both mtDNA and nuclear DNA of. Thus, the Thorny Devil is in the mesic ( moisture- loving, often in the rain forest ) Radiation of the Australian agamid the special position as the only drought- loving ( xerische ) way. While all the other people living in drylands, Australian Agamas (eg Pogona ) are combined in one taxon designated as Amphibolurinae, represents the evolutionary line to Thorny devil, an independent adaptation to drought in Australia dar. The Thorny Devil is probably the last survivor of a basal mesic group according to separating off molecular clock before 18 million years of the rainforest inhabitants.
The Thorny Devil is regarded as Australian equivalent of the horned lizard ( Phrynosoma ) in the arid regions of North America, which are also characterized by spikes and a diet of ants. It is convergent evolution, the genera Phrynosoma and Moloch are not closely related.